1. Field of the Invention
The present invention relates to cutting tools for the machining of metals and has more particularly for its object a milling cutter for machining T-shaped grooves.
2. Description of the Prior Art
Up to now, the machining of T-shaped grooves has always been a problem due to the lack of rigidity of the milling cutters available on the market, the head of which, particularly in the case of an embodiment having indexable hard metal inserts such as known today, has only a thin wall of material to support the said inserts. Therefore, the relatively great cutting forces to which these milling cutters are subjected, their head having been received in the piece to be machined, very rapidly generate vibrations, even at slow feed rate. Thus it has not been possible to use tools having hard metal indexable inserts without breaking the cutting edges of these inserts and as a consequence, the tool does not cut any more after a very short time. This is why milling cutters in high speed steel are now preferred which are more ductile than the sintered carbides, but it is evident that the efficiency of such tools is not comparable with the cutting performance that one can obtain with modern tools equipped with hard metal cutting inserts, such as tungsten carbide.
The small thicknesses of the aforementioned walls are due to the important void, traversing through all the axial height of the head of the milling cutter, which has been up to now been provided before each of the teeth to improve the formation and discharge of the chips. But as has been seen hereabove, these milling cutters are disadvantageously subject to vibrations since these walls bend during cutting, the said vibrations accelerating the wearing off of the cutting edges of the tool.